Interlocking switch mechanism



Patented June 28, 1927.

UNITED STATES PATENT OFFICE.

OF RAMSEY COUNTY, MINNESOTA.

ASSIGNOR TO AMERICAN HOIST & J..J'OHNSON AND W. O. WASHBURN,

INTERLOCKING SWITCH MECHANISM.

Application filed August 2,1924. Serial No. 729,807.

This invention relates to new and useful improvements in interlocking switch mechanisms particularly adapted for use in connection with ordinary knife switches such as are commonly used to control electric circuits, and more particularly relates to such a device which is operable in conjunction with a plurality of switches such as are commonly employed in conjunction with electric rivet heaters or other electric heaters, which usually vhave a plurality of different heats and therefore a like number of control switches in order that any one of the different heats may be used independently of the others.

In the operation of multiple switch mechanisms such as are commonly employed at present to control a plurality of circuits, extreme care must be exercised in the manipulation of the switch levers to prevent more than one switch or circuit being closed at a time. Should two or more circuits be closed at one time serious damage mayabe caused as a result of short-circuitin' gand burning out some of the coils or windings which would render the apparatus-inoperative. It is therefore desirable *that'means be pro-j vided whereby it will be impossible, to effect the closing of more than one such switch, and therefore circuit-ate. time:

The primary object of this invention, therefore, is to provide an improved. interlocking switch mechanismrwhich'may readily. be applied to an ordinary multiple knife switch having a plurality of manuallyropere; able switch control levers for-the, purpose: of positively preventingmorethan one of the control levers thereof from being-moved into switch closed position at the same time;

A further and more specific object of the; invention is to provide such a-device of simple and inexpensive construction having means operable in conjunction therewith to, yieldably retain the switch levers in eitheropen or closed position.

Other objects of the invention will more Fully appear from the following description and the accompanying drawings and will be.

pointed out in the annexed claims;

In the drawings there has been disclosed a structure designed to carry out the objects of the invention, but it is to be understood that the invention is not=confined to the exact Structure shown, as various changes may be made in the scope of the claims which Q follow.

In the, accompanying-drawings forming a part of this specification,

Figure 1 is a plan view of a multiple :WltChIShOWlIlg my invention applied thereo j v Figure 2 is'a cross-sectional view on the l1ne;2 2 of Figure 1 showing all of the switches, in open position; 1

Figures-3,"4 and 5 are similar views to show the different positions assumed by the parts when the various switches are actuated. In theselectedembodiment of the invention here shown,- for purposes: of disclosure, there is illustrated a multiple switch of ordinaryconstruction comprising a-case or cabinetv 6 having an insulated-vpanel 7 mounted therein upon which the switches are mounted. lThe switchesl-herdshown are similar in constructionand it will therefore-be necessaryito describe-but one, like parts being indicatedi by-wlike numerals. Each switchpreferablyvconsists' of a lever 8 pivotally mounted'betlween: lugs 9 i1pon a subpanel 11 WlllCh-dSSBCUIBd to the-panel 7 by means of scr'eWsi12tfiThe lugs'9 of the series of switches are i electrically connected together 'by meanj'ss'ofwa'bar' 13 secured thereto bv screws l l as shown in Figure 1. '"The'usual contacti fingers15-arevsecured to the lever 8 and-are; adaptedto be movedinto and out of contact with' theixstationary contacts 16 secured to the s'ubpanel 11. 'One' side of'the power lineisiconnected .tothe bar 13 and the other SldfiwtO the stationary: contacts 16 so that whe'n :the' switch-1ever'8 is in closed positlon-as {shownin :Figure' 1, tlie'cur rent will flowefromihe bar 13' through the lever 8 a to the stationary contact 16- and therefore the other side of the line. An insulated hand a grip or handle; 17 is secured to each switch means of'whichuthe'y may belever,-8 by manually! operated.--These handles preferably outwardly-1 project through elongated apertures 18 provided in the wall of the cabinet as shown in Figures 2, 3-, 4, and 5.

An important feature; of this invention residesin the novel means provided for positively preventing more than one switch from being moved into closing position at one time,and also for switch levers in eitheropen or closed position. Such means preferably consists in the yieldably retaining the provision of a series of yokes, or spring controlled latch members 19,21, and 22 which are pivotally mounted upon studs 23, 24 and 25, respectively, as shown in thB VaIIOQS 6 figures For convenience in describing this mechanism and its operation the switch handles 17 will be hereinafter referred to by the letters A, B, and C. Each yoke is yield.- ably held in switch-opening or closing posilo tion by means of a spring 26 having one end pivotally connected thereto by means of a pin 27 and its other end secured to the wall of the casing; The fingers 28 of each yoke are adapted to straddle its complementary [.3 switch handle so that movement of the switch handle will cause its respective yoke to oscillate upon'its pivot. Thus each lever has connected therewith a pivoted spring controlled latch member adapted to posi- 20 tively yieldably maintain.the lever at-opposite switch control limitsafter manual starting.- An L-shaped arm, or bell crank lever as arock-member or pivoted arm, 29 is pivotally mounted upon a'stud 31 secured to 1 thecasinig'wall and this arm is connected, bymeans of a link -32, to a T-shaped rock member or pivotedarm 33 which is pivotally inounted upon the stud 24 upon which the yokev 21- is-mounted-r-A rock arm or element m Mrissimilarlymounted upon the stud 31, thesopposed ends of whichr ar e; adapted to 1:: engagethe switch handlesz'Ai and' B? zvlniFigure 2, .the parts are shown in inop e'rative position, i'nsa: row. at a. position herein 3:. designated .normal7 or switchropen posi tion; with the movable contacts out'of en'-' gngemenfi with-the stationary' contacts 16; their thus positioned, thes witch handles A, 13,2? andrC first, second and th'ird -will"b'e 4o moved:- 2H1 ;tl'1e--:outer- -orlower 'end of the elongatedjopeningsflB a'nd willi be grann heldinisuch position-bynmea'risof the .26;, as a result ofZthe pins '27' oscillatingabont the axes. :of the pivotsi23'y2 t and 25 of the yoke's=-19, '21- and 22, respectively, thereby tending to elongate thesprin'gs 26'jas"th'ey-I pass lover the pivots 23.? soon=' as-'the springs pass'over the" pi vots'23the fingers 28 ofwthe-yokes 19. 21 and 22'will 'be-"downso wardlyi moved to i the *position here shown; caused-by? the action of'the'springs 26 as they C'ontIa'ctiEeJ J T ii F Alli-Figure 3,1116 switch Handles-is shown; in switch-closing position wherein the fingers 2& of the yoke 19 have been upwardly inov'ed' and "in which position the haniile A will be yieldably held against the end of the slot gated opening 18; the switch handle A is moved-from-the position shown in Figure W 2 to that shown in Figure'3, itwill en age the reduced end portion35 (see Fig. 4%, of the L-shaped' arm '29 and move it -to the position here shown; th e lever-34 and thjegT-shaped arm 33 will also be actuated by'means of the line 32.

When thus actuated,

In Figure 4, the switch handle 13 is shown as having been moved to switch-closing position in which position it also is yieldably held against the end of the elongated opening 18 by the action of the spring 26. \Vhen the switchhandleB is moved from the position shownin Figures 2 and 3 to that shown in Figure 4, it will engage one end of the rocker-arm 34: and upwardly move it as here shown, while the other end of the rocker-arm 34 will engage the switch handle A and downwardly move it to switch-opening position as shown in this figure. \Vhen thus positioned, the switch handles A and B will be yieldably held in their respective switch-opening and switch-closing positions by means of the springs 26.

In Figure 5, the switch handle C is shown in switch closing position and the switch handles A and B in inoperative or switchop'ening' posit ion. \Vhen the switch handle (a is moved to the position here shown from that shown in Figures 2, 3 and 4, it will ongage one sideof'the T-shaped head of the arm 33 while-the other side of the T-shaped head will engage the switch handle B and downwardly move it to the position here shown in which" position the two switch handles and Gwill in like manner he yieldably held in the-ir respective positions. Thus it will" readily bo' seen that by the employment ofthis novel interlocking mechanism any 'o'neof the series of switches may be selectively nioved into closing position and also'jtha't itwill beimpossible for more than onesw itch to-be 'inoved'into such position at one time-'"Refei'ring to Figure 5, it will beseen that-should the switch handle A be ihovedinto switch-closing position as shown in Fig u're 3, it wilhengage the reduced end portion 35 of the l shaped arni29 which wil'l' 'ca' is'e' said ami' tbi oscillate' upon the pivotp1n31 wilteflect milai'fopcra-ti'on of the T- shapeda l 3 asaresu'lt'o'f the link connetion therebetweenl lsuch =osci llation of the T'shap'ed ""al-"nr'33' {will therefore" cause the one side bf'theT s'haped head to engage the switbh handle it-to;switclpopeningposition as shown in Eigures-2j3 and 4;-"-'

-In"the 'drawing's'-, I have'sho n this novel switeh 'mechanisin' as' applied to a multiple switch comprising three switch levers, It is to be'understood;'however3 that-"it may be used in conjunction with any number of switch levers'by simply increasing or decreasing'the number of parts; depending. of course, upon theinumber of switch levers with which it i's'to be used. 1

I claim as'myinvention:

1.' A device of the class described comprising three pivoted knife-edge switch levers first, second and third; said levers normally ali'ned at one throw limit, the levers being Such oscil'lation-of the arm 29 and downwardly move swingable "to anopp'osite throwlimit in planes parallel-to'one another through small arcs of=substantially equal length'a'nd in'the same direction. a first rockable element having an extension arranged across the-'path of I he fi rst lever, a second grockabl'e element hav ing extensions arranged respectively across thepatlis of" the first-' and second switch levers. said rockable elements having a common pi rot, a third I'ockable element having extensions across the paths of the second and third switch levers, said first and third rockable elements being connected for movement in unison, and spring controlled pivoted elements engaging the switch levers to hold the same at either throw limit and to snap the levers to those limits after movement has been manually initiated 2. A device of the class described comprising three pivoted knife-edge switch levers first, second and third levers normally alined at one throw limit, the levers being swingable to an opposite throw limit in planes parallel to one another through small arcs of substantially equal length and in the same direction, a first rockable element between the first and second switch levers having an extension arranged across the path of the first lever, a second rockable element having extensions arranged respectively across the paths of the first and second switch levers, said elements having a common pivot, a third rockable element between the second and third switch levers having extensions across the paths of said second and third levers, said first and third rockable elements being connected for movement in unison, and having extensions respectively normally lying near the first and second levers, and said second and third levers having extensions respectively normally lying at greater distance from second and third lovers.

3. A device of the class described comprising three pivoted knifeedge switch levers first, second and third, said levers normally alined at one throw limit, and being swingable to an opposite throw limit in planes parallel to one another and in the same direction, a first rockable element having an extension arranged across the path of the first lever, a second rockableelement having extensions arranged respectively across the paths of the first and second switch levers, said elements having a common pivot, a third rock able element havin extensions across the paths of the second and third switch levers, said first and third rockable elements being connected for movement in unison, the connection being made on that side of the levers adjacent the normal throw limit.

4. A device of the class described comprising three pivoted knife-edge switch levers first, second and third, said levers normally alined at one throw limit, and being swingable to an opposite throw limit in planes parallel to -'one another and in the same direction,a first rockable element having an extension arranged across the path of the firstlever, a second 'rockahle element having extensions arranged respectively across the pathswotthe" first and second switch levers, a third rockable element having extensions across the paths of the second and third switch levers, said first and third rockable elements being connected for movement in unison, all extensions lying the same side of the levers.

5. A device of the class described comprising three pivoted knife-edge switch levers first, second and third, said levers normally alined at one throw limit, and being swingable to an opposite throw limit in planes parallel to one another and in the same direction, a first rockable element having an extension arranged across the path of the first lever, a second rockable element having extensions arranged respectively across the paths of the first and second switch levers, said elements having a com mon pivot, a third rockable element having extensions across the paths of the second and third switch levers, said first and third rockable elements being connected for movement in unison, said rockable elements being normally slanted in a direction generally toward the first switch lever.

6. A device of the class described comprising three pivoted knife-edge switch levers first, second and third, said levers normally alined at one throw limit, and being swingable through small arcs of substantially equal length, and in the same direction, to an opposite throw limit, a first rockable element having an extension arranged across the path of the first lever, a second rockable element having extensions arranged respectively across the paths of the first and second switch levers, said elements having a common pivot, a third rockable element having extensions across the paths of the second and third switch levers, said first and third elements being connected for move ment in unison through substantially equal arcs, and spring controlled pivoted elements engaging the switch levers to hold the same at either throw limit and to snap the lovers to those limits after movement has been manually initiated.

7. A device of the class described comprising three pivoted knife-edge switch levers first, second and third, normally alined at one throw limit, the levers being swingablc through small arcs in the same direction, to an opposite throw limit, a first rockable element having an extension arranged across the path of the first lever, a second rockable element having extensions arranged respectively across the paths of the first and sec- 0nd switch levers, a third rockable element between the second and third switch levers having extensions across the paths of the second and third switch levers, said first and third elements being connected for movement in unison, the extension of the first, and one extension of each of the second and third rockable elements overlying the first and second levers and-being initially nearer those levers, and the other extensions being 10 farther respectively from the second and third levers.

In witness whereof, I have hereunto set my hand this 30th day of July 1924.

JOHN E. SEDERHOLM. 

